【作者】 魏巍；

【导师】 杨旭东； 曲淑岩；

【作者基本信息】 长春工业大学 ， 资源与环境硕士（专业学位）， 2023， 硕士

【摘要】 随着人口的过度增长、科技和工业的发展,致使自然环境遭到了巨大的损害。而重金属又以各种形式和状态广泛存在于社会环境和自然环境中,对环境和我们的地球村造成了严重影响。大量的重金属被农业污染物和工业废气污染了整个生态环境。采用不同的技术手段,可以有效地消除水体中的重金属污染物,并进行检测。为了有效地保护我们的环境,研究出一种高效、安全、经济的技术手段,以便准确地检测和控制生态系统中的重金属污染。光致发光的碳点和纳米簇作为新型的荧光材料具有广阔的应用前景,由于他们吸引人的特征而备受关注。然而,其复合材料的发展仍存在一些困难与阻碍,基于碳点和铜纳米簇的有效荧光信号放大方案的开发具有挑战性,因此开发出新型的荧光纳米复合材料是非常重要的。本论文主要研究内容如下:在第一部分工作中,以邻苯二胺为碳源,磷酸为钝化剂,制备了发射红色荧光的碳点(CDs),然后加入硅藻土(Diatomite),通过一步水热法成功制备了具有信号放大能力和更高荧光量子产率的碳点/硅藻土纳米复合材料(CDs/Diatomite)。合成的CDs/Diatomite纳米复合材料通过SEM、FT-IR、XRD、Raman、UV-Vis和荧光技术对其进行了表征。所得CDs/Diatomite纳米复合材料水分散性好,光致发光稳定。结果表明,硅藻土包覆CDs后,CDs的荧光量子产率由10.1%提高到32.3%。CDs/Diatomite纳米复合材料对水溶液中的六价铬离子具有选择性和灵敏的荧光猝灭行为并且对六价铬离子的传感灵敏度有显著提高。随着Cr(VI)浓度的不断升高,CDs/Diatomite纳米复合材料的六价铬离子的检测限达到了0.15μM,而在365 nm紫外灯的照射下,它的荧光颜色也从原本的红色转变成了深黑色。此外,为了增强其可视化和方便性,还开发出了一种Cr(VI)检测试纸,可拓展CDs/Diatomite纳米复合材料在环境检测等方面的应用效果。在该部分工作中,首先,以D-青霉胺为配体制备了铜纳米团簇(Cu NCs),基于量子限域效应将其掺杂进硅藻土的孔隙中,得到了荧光更强和更高荧光量子产率的铜纳米簇/硅藻土纳米复合材料(Cu NCs/Diatomite)。制备的Cu NCs/Diatomite纳米复合材料在波长为340 nm的光激发下发出波长为650 nm的红色荧光。基于铜纳米团簇的荧光纳米复合材料不仅可以增强Cu NCs的荧光发射强度,并且增强了其猝灭效率。此外,为了增加其方便性和可视化,将聚乙烯醇(PVA)和Cu NCs/Diatomite纳米复合材料复合,室温下,静止12 h,成功制得了红色光致发光的荧光纳米复合薄膜(Cu NCs/Diatomite/PVA)。通过实验我们发现,将Cu NCs/Diatomite/PVA复合薄膜的Cu NCs会与Cr(VI)反应,随着Cr(VI)的不断加入,Cu NCs/Diatomite/PVA荧光复合薄膜的荧光强度慢慢降低,在紫外线灯下,我们可以看到红色荧光的显著减弱直至荧光猝灭。而通过这些现象,能够完成对水环境中Cr(VI)的特异性检测。Cu NCs/Diatomite/PVA在日光下的颜色由乳白色变为棕黄色。更多还原

【Abstract】 With the excessive increase of population,the development of science and technology and industrialization,the natural environment has been greatly damaged.Heavy metals exist widely in social and natural environments in various forms and states,causing serious impact on the environment and our global village.A large number of heavy metals have been polluted by agricultural pollutants and industrial waste gases.Using different technical means,the heavy metal pollutants in water can be effectively eliminated and detected.In order to effectively protect our environment,an efficient,safe and economical technical means has been developed to accurately detect and control heavy metal pollution in the ecosystem.As new fluorescent materials,photoluminescent carbon dots and nanoclusters have broad application prospects and have attracted much attention due to their attractive characteristics.However,there are still some difficulties and obstacles in the development of its composite materials.The development of effective fluorescence signal amplification schemes based on carbon dots and copper nanoclusters is challenging,so it is very important to develop new fluorescent nanocomposites.The main research content of this paper is as follows:In the first part of the work,using o-phenylenediamine as carbon source and phosphoric acid as passivating agent,the carbon dots(CDs)emitting red fluorescence was prepared,and then diatomite was added.The carbon dots/Diatomite nanocomposite(CDs/Diatomite)with signal amplification ability and higher fluorescence quantum yield was successfully prepared by one-step hydrothermal method.The CDs/Diatomite nanocomposites were characterized by SEM,FT-IR,XRD,Raman,UV-Vis and fluorescence techniques.The obtained CDs/Diatomite nanocomposites have good water dispersion and stable photoluminescence.The results showed that the fluorescence quantum yield of CDs increased from 10.1% to 32.3% after diatomaceous earth coating.CDs/Diatomite nanocomposites have selective and sensitive fluorescence quenching behavior for hexavalent chromium ions in aqueous solution,and significantly improve the sensitivity to hexavalent chromium ions.With the increasing of Cr(VI)concentration,the detection limit of Cr(VI)ions in CDs/Diatomite nanocomposites reached 0.15 μM,and its fluorescence color changed from red to dark black under the irradiation of 365 nm UV lamp.In addition,in order to enhance its visualization and convenience,a Cr(VI)test paper is also developed,which can expand the application effect of CDs/Diatomite nanocomposites in environmental detection and other aspects.In this part of the work.Firstly,copper nanoclusters(Cu NCs)were prepared using D-penicillamine as the preparation system,which were doped into the pores of Diatomite based on quantum limited effect,and the copper nanoclusters/Diatomite nanocomposites with enhanced fluorescence and higher fluorescence quantum yield were obtained.The prepared Cu NCs/Diatomite nanocomposites emit red fluorescence at a wavelength of 650 nm under the excitation of 340 nm light.The fluorescence nanocomposites based on Cu NCs can not only enhance the fluorescence emission intensity of copper nanoclusters,but also the quenching efficiency was enhanced.In addition,in order to increase its convenience and visualization,the composite of polyvinyl alcohol(PVA)and Cu NCs/Diatomite nanocomposite material,at room temperature,static 12 h,successfully obtained red photoluminescent fluorescent nanocomposite film(Cu NCs/Diatomite/PVA).By experiments,we found that Cu NCs/Diatomite/PVA composite film reacts with Cr(VI).With the continuous addition of Cr(VI),the fluorescence intensity of Cu NCs/Diatomite/PVA composite film slowly decreases.Under the UV lamp,we can see that the red fluorescence is significantly weakened until the fluorescence quenching.Through these phenomena,specific monitoring of Cr(VI)in water environment can be detected.The color of Cu NCs/Diatomite/PVA changes from milky white to brownish yellow under sunlight.更多还原